The Amide Group as Modulator of Crystalline and Liquid Crystalline Structures in Isocyano-Alkylanilide Silver(I) Complexes

Silver­(I) complexes [AgX­(CNR] and [Ag­(CNR)2]­X (X = anionic ligand), containing an amide-functionalized isocyanide, CNR = CN–C6H4–NHCOR, have been synthesized and their X-ray structures have been determined for [Ag­(X)­(CN–C6H4–NHCOCH3)] (X = NO3–, CF3SO3–) and [Ag­(CN–C6H4–NHCOCH3)2]­X (X = NO3–, CF3SO3–, BF4–). All the crystal structures show a packing of polymeric chains formed through Ag–OCamide interactions. These chains associate in layers through hydrogen bonds involving the amide group, and by further interactions of the metal ion with oxygen-donor moieties. Substitution of the Me group in the amide by a nonyl chain (R = C9H19) leads to neutral [Ag­(NO3)­(CN–C6H4–NHCOC9H19)] and ionic [Ag­(CN–C6H4–NHCOC9H19)2]­X (X = NO3–, CF3SO3–, H25C12OSO3–, BF4–) mesomorphic complexes. All of them display smectic liquid crystalline phases compatible with the crystal structures found for the methyl derivatives, and FTIR/ATR spectroscopy confirms that the intermolecular interactions observed in the solid state are preserved in the mesophase.